- Get into a cab
- Give the driver instructions
- Stare fixedly at the screen
- Push the 'Off' button when it comes on
What I discovered paying with a credit card (besides the fact that the RFID chip in my card scarily enough works, so now I have to be careful not to walk too near readers,) is that the machines themselves... well, I don't want to generalize based on one experience. But, I had a $5 tab. I hit the '20% tip' button, as it was easier than typing in $1, and that was what I would have given him anyway. It popped up as $2. I confirmed this was happening with a few more stabs at the touch screen, and then manually typed in the $1 tip.
So, these probably have a year or two to go before they're trustworthy.